Rock drill for recovering samples



Jan. 14. 1969 JAMES E. WEBB ,4 ,5

ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ROCKDRILL FOR RECOVERING SAMPLES Filed Dec. 27, 1966 United States Patent3,421,591 ROCK DRILL FOR RECOVERING SAMPLES James E. Webb, administratorof the National Aeronautics and Space Administration with respect to aninvention of Allen G. Ford, Pasadena, Calif.

Filed Dec. 27, 1966, Ser. No. 605,097

US. Cl. 175-323 Int. Cl. E211) 17/00; E21c 13/104; E21c 13/06 9 ClaimsABSTRACT OF THE DISCLOSURE The invention described herein was made inthe performance of work under a NASA contract and is subject to theprovisions of Section 305 of the National Aeronautics and Space Act of1958, Public Law 85568 (72 Stat. 435; 42 USC 2457).

The present invention relates to an improved construction for rockdrilling apparatus, particularly useful for lunar and planetarysampling, for example, and it relates more particularly to an improvedrotary impact type of rock drill which is capable of recovering rockcuttings from the cutting zone and raising the cuttings to the surfacefor analysis or disposal.

In the construction of most rock drilling apparatus it is usuallynecessary to provide some means for removing the rock cuttings from thecutting zone at the bottom of the drilled hole. The removal of the rockcuttings is usually necessary so that the cuttings themselves may beanalyzed, and also so that the drilling operation may be continuedunimpeded.

In the past it has been conventionally known to employ some means, suchas an inclined ramp, conveyor or rotating spring to remove rock cuttingsfrom the cutting zone at the bottom of a drilled hole. Also, it has beenpreviously proposed that rock cuttings be removed from the bottom of adrilled hole by introducing compressed air through the drillingapparatus itself. Compressed air would be introduced with sufiicientpressure to blow the rock particles up between the drill rod and anouter stationary sleeve surrounding the rod, to an exit port at thesurface.

However, the prior art systems and mechanisms, such as those enumeratedabove, have, for the most part, proven to be not only complicated andexpensive, but additionally, have proven to be relatively inefficient intheir operation.

The drill assembly of the present invention provides a simple andinexpensive means for removing rock cuttings from the cutting zone, andfor raising the cuttings up, out and clear of the drilled hole. Theuseful end results for the rock drill assembly of the invention areachieved in accordance with the concepts of the invention included inthe embodiments to be more fully described hereinafter, by the provisionof sawtooth-shaped threads on the outer surface of a drill rod, and bythe provision of similar juxtaposed threads on the inner surface of acoextensive stationary sleeve which surrounds and is coaxial with thedrill rod.

In accordance with the concepts of one embodiment of the rock drillassembly of the invention, the drill rod, to be described more fullyhereinafter, is rapidly driven in the axial direction in a reciprocalmanner, and at the same time is rotated slowly. The rapid reciprocal androtary Patented Jan. 14, 1969 ice motion imparted to the drill rod is inaccordance with known and usual rock drilling drive motion.

In accordance with the concepts of another embodiment of the rock drillassembly of the invention the drill rod is suspended freely, by opposingspring members, within a coextensive stationary sleeve which surroundsand is coaxial with the drill rod. In this embodiment of the inventionthe impact energy, and the rapid reciprocal and rotary drive motion,imparted to the drill bit is transmitted through collar and sleevemembers to the bit while the rod is suspended freely to vibrate withinthe sleeve member, independently from all impacting or driving motion.

In both embodiments of the rock drill assembly of the inventionillustrated in the drawings, the exterior surface of the dri.l rod andthe inner surface of the sleeve which surrounds and is coaxial With thedrill rod are provided with sawtooth threads so configured that theupper surfaces of the threads are essentially horizontal and normal tothe vertical axis of the drill rod and sleeve, and the lower surfaces ofthe threads taper at a steep angle. The threads provided on the drillrod and on the sleeve have the same pitch.

In the embodiment of the invention wherein the drill rod and surroundingsleeve are driven by the same rapid reciprocal and rotary drive motionthe threads on the drill rod and sleeve are positioned so that the tipsof the rod threads and the tips of the sleeve threads are staggered. Asthe drill assembly is subjected to an axial vibratory motion, rockparticles in the annular space between the rod and sleeve are propelledupward by the flat upper surfaces of the threads on the rod and sleeveand deflected radially by the slanting lower surfaces of the threads. Inthis manner rock particles progress up through the sleeve on as.ep-by-step basis and are discharged through an exit orifice providedin the upper portion of the rock drill.

An object of the present invention, therefore, is to provide an improvedrock drill which is constructed so as effectively to remove rockcuttings from the rock cutting zone, and to elevate such cuttings clearof the drilled hole to the surface; this being achieved in a simple,inexpensive, and yet most elficient manner.

Other objects and advantages of the invention will become apparent froma consideration of the accompanying drawings, in which:

FIGURE 1 is a side sectional elevation of an impact type rock drillconstructed in accordance with the concepts of one of the embodiments ofthe invention;

FIGURE 2 is a cross-sectional view of the lower end of the drillassembly of FIGURE 1 taken substantially along the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary side sectional view showing the lower portionof an alternate embodiment of an impact type rock drill constructed inaccordance with the concepts of the invention;

FIGURE 4 is a fragmentary side sectional view showing the upper portionof the alternate embodiment of the impact type rock drill shown inFIGURE 3;

FIGURE 5 is a cross-sectional view of the lower end of the rock drillshown in FIGURE 3 taken substantially along the line 5-5 of FIGURE 3;

FIGURE 6 is an enlarged section of the drill rod, and the sleeve coaxialtherewith, showing the thread configurations on the rod and sleeve.

Referring to the drawings it is seen that the rotary im pact rock drillassembly of the invention includes an elongated drill rod 1%. In theembodiment shown in FIG- URES 1 and 2 the drill rod 10 is driven by anexternal drive means, not shown, which imparts rapid reciprocal linearmotion to the drill rod and, at the same time, imparts a relatively slowrotational movement to the rod.

In the embodiment shown in FIGURES 1 and 2, the drill rod 10 issurrounded by a stationary sleeve 16 which is coextensive and coaxialwith the rod. As shown in FIG- URE 1, the lower extremity of the sleeve16 extends into a drill bit 12. The upper portion of the drill bit 12extends into, and is retained by the rod 10. The hardened steel bit 12is mounted on the lower extremity of both the drill rod 10 and sleeve 16by brazing or by other suitable means.

In the embodiment of the invention shown in FIG- URE 1 the housing 20 issolidly attached to the drill rod 10 and sleeve 16 by brazing or byother suitable means. Key members 38 appropriately spaced at intervalsof 120, for example, within the drill rod 10 provide further rigidsupport for the drill assembly. In the embodiment of the invention shownin FIGURES 3, 4 and 5 the housing 20 is solidly attached to the sleeve16 by brazing or by other suitable means but the drill rod is suspendedfreely within the sleeve 16 and housing 20, and is therefore notattached to the housing 26 as is the drill rod 10 of the embodiment ofthe invention shown in FIGURE 1. As shown in FIGURES 1 and 4 the lowerportion of the housing may be provided with an outwardly taperedconfiguration so as to define a flange 20a.

The cutting zone of the rock drill assembly is at the bottom of thedrilled hole and as the moving parts of the drill are rapidly driven ina reciprocal manner in an axial direction, and at the same time rotatedslowly, the impact of the bit 12 on the rock at the cutting zone loosensand pulverizes the rock. The action of the rock drill causes rockfragments, or cuttings, to be produced at the cutting zone.

As best seen in FIGURES 2 and 3 the bit 12, rod 10 and sleeve 16 are soconfigured that an annular transport chamber 14 exists between the rod10 and sleeve 16. As the drill assembly is moved reciprocally, andsimultaneously rotated, rock fragments or cuttings at the bottom of thedrilled hole are caused to move into the annular transport chamber 14between the rod 10 and the sleeve 16. The lower faces of the rod 10 andthe sleeve 16, as best seen in FIGURE 2, are contoured so as to guidethe rock fragments or cuttings 30, seen in FIGURE 3,, into the annulartransport chamber 14.

In accordance with the concepts of the present invention, projectionmeans are formed on the inner surface of the sleeve 16. These projectionmeans extend along the entire length of the sleeve. The projection meansmay be, for example, in the form of threads 22, as illustrated, having asawtooth configuration so as to provide a series of essentiallyhorizontal shelves around the inner peripheral surface of the sleeve 16extending from one end of the sleeve to the other.

Similarly, projection means are formed on the outer surface of the drillrod 10 in juxtaposition with the projection means 22. The projectionmeans provided on the outer surface of the drill rod 10 may take theform of threads 24, as illustrated, having a sawtooth configuration soas to provide a series of essentially horizontal shelves around theouter surface of the drill rod 10.

Referring to FIGURE 6 which shows an enlarged section of the projectionmeans, or threads, provided on the rod 10 and sleeve 16 it is seen thatboth the threads 22 and 24 have upper surfaces which are essentiallyhorizontal, and therefore normal to the vertical axis of the rod 10 andsleeve 16, and have lower surfaces, 28 and 26 respectively, which taperat a steep angle. The threads 22 and 24, as best shown in FIGURE 6, areprovided with the same pitch and are so positioned that the end tips ofthe threads 22 are staggered in relation to the tips of the threads 24.

In the operation :of the rock drill assembly the hardened steel bit 12of the drill assembly is pressed firmly against the rock or othermaterials to be broken, cut, pulverized and lifted 'by the drill, As thedrill assembly is driven by an external drive means, not shown, a rapidreciprocal linear motion, and a relatively slow rotary motion, isimparted to the drill assembly. The rapid reciprocal linear motionimparted to the drill assembly causes the drill bit 12 to exert a highinstantaneous pressure against the rock face or other surface to bedrilled causing particles of that surface to be sloughed off andpulverized by the drill. The reaction of the drill on the hard surfaceof the rock or other material to be cut causes a reinforced vibratorymotion to be imparted to the drill assembly.

Rock particles are guided into the annular transport chamber 14 betweenthe rod 10 and sleeve 16 by the contoured lower faces of the rod 10andsleeve 16, as best seen in FIGURE 2. As the drill assembly is beingstirsjected to axial vibratory motion the rock particles 30 in theannular transport chamber 14 are being propelled upward 'by the flatupper surfaces of the threads 22 and 24 and deflected radially by thetapered lower surfaces 28 and 26 of the threads 22 and 24 respectively.In this manner the broken, cut and pulverized particles 30aretransported step 'by step upwardly until these particles reach thedischarge port 32 provided in the housing 20 of the drill assembly.

A constructed embodiment of the drill assembly shown in FIGURES 1 and 2has been found to operate with'a high degree of efliciency in providinga flow of cuttings from the cutting zone, through the annular transportchamber 14 and through the discharge ports 32 for disposal where thecuttings are discharged and collected for analysis. Moreover, theassembly is extremely simple in its construction, and involves noextraneous parts or components, and merely requires the suitableconfiguration of the drill rod 10 and sleeve 16, as described above.

The embodiment of the drill assembly shown in FIG- URES 3-5 is generallysimilar to the embodiment shown in FIGURE 1, and like components of thetwo embodiments have been indicated by the same numbers. The embodimentof the drill assembly shown in FIGURES 3-5, however, includes a drillrod 10 which is suspended freely within a housing 20 and sleeve 16 byopposing spring members 42 and 46. The lower spring 42 is mounted Withinthe housing 20 immediately above discharge ports 32 provided in thehousing. The lower end of the spring 42, as seen in FIGURE 4, bearsagainst the housing 20, and its upper end bears against the under sideof a flange 44 provided on the upper end of the drill rod 10. The upperportion of the housing 20 as seen in FIGURE 4 is closed by a cap member48. The upper portion of the housing 20 and the cap member 48 may beprovided with screw thread engaging structure, for example, as shown inFIGURE 4, so that the cap member 48 may be removed from the housing 20for facilitating the removal, repair, replacement and/or maintenance ofany of the structural members within the drill assembly of the in-'vention.

As shown in FIGURES 3 and 5, the lower portion of the drill rod 10 isprovided with a slot 40. The slot 40 is made of appropriate size so thatthe drill rod 10 is free to vibrate with rapid reciprocal motion abovethe drill bit 12 without becoming bound to the drill bit and withoutinterfering with the cutting operation of the drill bit. However, as'best seen in FIGURES 3 and 5, the bit 12 is solidly attached tothesleeve 16 by brazing or by other suitable means. Similarly the sleeve 16is solidly attached to the housing 20 by brazing or by other suitablemeans.

The drill assembly of the invention as shown in FIG- URES 3-5 is drivenby an external drive means not shown in the drawings. The external drivemeans imparts a rapid reciprocal linear motion, and a relatively slowrotary motion to the drill assembly. Since the drill rod 10 is providedwith a slot 40 for engaging the drill bit 12 the drill rod 10 will bedriven by the same rotary motion as that imparted to the drill assemblyby the external drive means, not shown in the drawings. However, sincethe drill rod 10 is suspended freely within the housing 20 and sleeve 16the drill rod vibrates with reciprocal linear motion which isindependent of the reciprocal linear motion imparted to the housing 20,sleeve 16 and drill bit 12 by the external drive means not shown in thedrawings. The reciprocal linear motion of the drill rod within the drillassembly is guided by the spring members 42 and 46, the housing 20, keymembers 38, shown in FIGURE 1, appropriately spaced at intervals of 120,for example, within the drill rod 10, and the side walls of the slot 40within the drill rod 10 which fits over the drill bit 12.

It has been found that if vibrations of the drill rod 10 are dampenedout to rapidly due, for example, to the structure of the material at thecutting zone, that the efficiency of the drill assembly to transport thecuttings to the surface may be somewhat impaired. However, by suspendingthe drill rod 10 freely within the housing 20 and sleeve 16 by opposingspring members 42 and 46, as shown in FIGURES 3-5, axial vibration ofthe drill rod may be established to any desired degree by an appropriateselection of the spring members 42 and 46. Thus the embodiment of thedrill assembly of the invention as shown in FIGURES 3-5 provides forefficient transportation of cuttings from the cutting zone to thedischarge ports 32 of the drill assembly for all conditions of materialat the cutting zone.

It will be appreciated, of course, that while particular embodiments ofthe invention have been shown and described, modifioations may be made.It is intended in the following claims to cover all such modificationsas fall within the permissible range of equivalents in accordance withthe scope and spirit of the invention.

What is claimed is:

1. A rock drill assembly including:

a vertical sleeve;

first projection means comprising a plurality of substantiallyhorizontal upward facing surfaces formed on the inner surface of saidsleeve and extending axially along at least a portion of the lengththereof;

a drill rod vertically mounted within said sleeve and rigidly attachedthereto;

second projection means comprising a plurality of substantiallyhorizontal upward facing surfaces formed on the outer surface of saiddrill rod in juxtaposition with said first projection means andextending axially along at least a portion of the length of said rod;and

a bit mounted on the lower end of said sleeve for drilling rock at acutting zone and producing rock cuttings when applied to the cuttingzone, said bit being configured to feed such cuttings into the spacebetween said rod and said sleeve when said bit is driven in a reciprocalaxial motion;

said first and said second projection means elevating said cuttings in astep-by-step manner from one level to another within said rock drillassembly until said cuttings are discharged from said rock drillassembly.

2. The assembly defined in claim 1 in which said first and secondprojection means are in the form of threads having a sawtooth section.

3. The assembly defined in claim 2 wherein said threads have uppersurfaces which are essentially horizontal and normal to the verticalaxis of said sleeve and said rod and have lower surfaces which taper ata relatively steep angle.

4. The assembly defined in claim 2 wherein the end tips of said firstprojection means are staggered in relation to the end tips of saidsecond projection means.

5. The assembly defined in claim 1 and which includes a housingsurrounding said drill rod and said sleeve at a position displaced fromsaid bit, said housing defining an exit port for said cuttings.

6. The assembly defined in claim 1 in which said bit is attached to saidsleeve and to said drill rod.

7. The assembly defined in claim 1 including means for driving saidassembly so that a reciprocal linear movement and a rotational movementare imparted to said assembly.

8. A rock drill assembly including:

a vertical sleeve;

first projection means comprising a plurality of substantiallyhorizontal upward facing surfaces formed on the inner surface of saidsleeve and extending axially along at least a portion of the lengththereof;

a drill rod vertically mounted within said sleeve and suspended freelytherein by means including opposed springs;

second projection means comprising a plurality of substantiallyhorizontal upward facing surfaces formed on the outer surface of saiddrill rod in juxtaposition with said first projection means andextending axially along at least a portion of the length of said rod;and a bit mounted on the lower end of said sleeve for drilling rock at acutting zone and producing rock cuttings when applied to the cuttingzone, said bit being configured to feed such cuttings into the spacebetween said rod and said sleeve when said bit is driven in a reciprocalaxial motion;

said first and said second projection means elevating said cuttings in astep by step manner from one level to another within said rock drillassembly until said cuttings are discharged from said rock drillassembly.

9. The assembly defined in claim 8 including means for driving saidassembly so that a reciprocal line-ar movement and a rotational movementare imparted to said assembly.

References Cited UNITED STATES PATENTS 1,501,706 7/1924 Zubiria 323 X1,926,038 9/1933 Culshaw 175394 1,932,239 10/1933 Berry 175323 X2,250,671 7/1941 Joy 175-323 X 2,594,256 4/ 1952 Compton 175--394 X2,830,795 4/ 1958 Center 175394 X 3,228,200 1/ 1966 Dufresne 175-394 XFOREIGN PATENTS 375,221 5/1923 Germany.

CHARLES E. OCONNELL, Primary Examiner.

IAN A. CALVERT, Assistant Examiner.

U.S. Cl. X.R.

